Paving machine with smart steering control

ABSTRACT

A smart steering control system a paving or texturing machine receives path elements corresponding to current and future positions of the machine. By comparing the current and future elements, an expected completion time is derived for exiting the current position and entering the future position; the smart steering control system synchronizes adjustments of the machine&#39;s steerable tracks from the current path to the future path. The smart steering control system functions as a virtual tie rod, preventing damage, enhancing the traction control and pulling power of the machine, and preserving the operating life of its components.

PRIORITY

The present application claims the benefit under 35 U.S.C. § 119(e) ofU.S. Provisional App. No. 62/447,153 (filed Jan. 17, 2017), which isincorporated herein by reference.

FIELD OF THE INVENTION

Embodiments of the inventive concepts disclosed herein are directedgenerally toward a paving and texturing machine configured forprogrammable control.

BACKGROUND

Some paving and texturing projects may require slipforming and/ortexturing around extremely small-radius curved surfaces. Regardless ofthe precise shape of the curved surfaces, which may include one or moreradii, straightline portions, spirals, or freeform curved elements, fora paving machine to successfully slipform or texture a curb (or gutter)according to these curved elements it must be possible to steer themachine around tight or variable curves. For example, the machine may besteered into a curved element in a counterclockwise (or left turn)direction, applying a curb mold or other tool to the curved surface at adesired position. Per the machine layout, while steeringcounterclockwise a left front track being closer to the radius of thecurved element than a rear track such that to enter the curve from astraightline position, the left front track must rotate 70 degrees andthe rear track 20 degrees. A steering controller may attempt to turn thelargest track angle at full drive, e.g., at 10 degrees/second; in thiscase, the left front track may take 7 seconds to reach its desiredposition. If the two tracks are unsynchronized, both tracks would reachthe 20-degree turn position in 2 seconds, and the target path elementwould not be maintained. An alternative solution, prorating trackrotation such that the left front rack is at 35 degrees when the reartrack is at 10, also fails to maintain the target path element.

It may therefore be desirable to synchronize track rotation with respectto the desired tool position, more effectively minimizing path trackingerror—the difference between where the tool needs to be and where itactually is.

SUMMARY

Embodiments of the inventive concepts disclosed herein are directed to asmart steering control system (smart steering controller, SSC) for apaving or texturing machine configured to apply one or more tools alonga path corresponding to a curved surface. The SSC may continuallyreceive path elements, either from a manual operator or from an externalsource (e.g., for remote or autonomous operations), corresponding tocurrent and future positions of the machine. The future position may bedirectly ahead of the current position or, if the machine is travelingin reverse, behind the current position. By comparing the current andfuture elements, an expected completion time may be derived for exitingthe current position and entering the future position (based, e.g., on aspeed of the machine). The SSC may then maintain the desired pathelement, minimizing path tracking error during the expected completiontime by synchronizing the adjustment of the rotational angles of themachine's steerable tracks from a setting corresponding to the currentpath element to a setting corresponding to the future path element. Inthis way, the SSC may function as a virtual tie rod whether the machineis under automatic or manual control and regardless of the path surface(straightlines, single and composite radii, spirals, freeform),preventing damage, enhancing the traction control and pulling power ofthe machine, and preserving the operating life of its components.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand should not restrict the scope of the claims. The accompanyingdrawings, which are incorporated in and constitute a part of thespecification, illustrate exemplary embodiments of the inventiveconcepts disclosed herein and together with the general description,serve to explain the principles.

BRIEF DESCRIPTION OF THE DRAWINGS

The numerous advantages of the embodiments of the inventive conceptsdisclosed herein may be better understood by those skilled in the art byreference to the accompanying figures in which:

FIG. 1 shows an overhead view of an exemplary embodiment of a paving ortexturing machine according to the inventive concepts disclosed herein;

FIG. 2 shows is a diagrammatic illustration of a tool carrier as in FIG.1;

FIG. 3 shows an illustration of the tool carrier of FIG. 1 in operation;

FIG. 4A shows an illustration of a locally referenced coordinatereference frame (CRF) of the tool carrier of FIG. 1;

FIG. 4B shows an illustration of short-radius operations of the toolcarrier of FIG. 1;

FIG. 4C shows an illustration of short-radius operations of the toolcarrier of FIG. 1;

FIG. 4D shows an illustration of short-radius operations of the toolcarrier of FIG. 1;

FIG. 5 shows an illustration of reverse operations of the tool carrierof FIG. 1;

FIG. 6 shows an illustration of clockwise operations of the tool carrierof FIG. 1; and

FIG. 7 shows an illustration of combination operations of the toolcarrier of FIG. 1.

DETAILED DESCRIPTION

Before explaining at least one embodiment of the inventive conceptsdisclosed herein in detail, it is to be understood that the inventiveconcepts are not limited in their application to the details ofconstruction and the arrangement of the components or steps ormethodologies set forth in the following description or illustrated inthe drawings. In the following detailed description of embodiments ofthe instant inventive concepts, numerous specific details are set forthin order to provide a more thorough understanding of the inventiveconcepts. However, it will be apparent to one of ordinary skill in theart having the benefit of the instant disclosure that the inventiveconcepts disclosed herein may be practiced without these specificdetails. In other instances, well-known features may not be described indetail to avoid unnecessarily complicating the instant disclosure. Theinventive concepts disclosed herein are capable of other embodiments orof being practiced or carried out in various ways. Also, it is to beunderstood that the phraseology and terminology employed herein is forthe purpose of description and should not be regarded as limiting.

As used herein a letter following a reference numeral is intended toreference an embodiment of the feature or element that may be similar,but not necessarily identical, to a previously described element orfeature bearing the same reference numeral (e.g., 1, 1a, 1b). Suchshorthand notations are used for purposes of convenience only, andshould not be construed to limit the inventive concepts disclosed hereinin any way unless expressly stated to the contrary.

Further, unless expressly stated to the contrary, “or” refers to aninclusive or and not to an exclusive or. For example, a condition A or Bis satisfied by anyone of the following: A is true (or present) and B isfalse (or not present), A is false (or not present) and B is true (orpresent), and both A and B are true (or present).

In addition, use of the “a” or “an” are employed to describe elementsand components of embodiments of the instant inventive concepts. This isdone merely for convenience and to give a general sense of the inventiveconcepts, and “a” and “an” are intended to include one or at least oneand the singular also includes the plural unless it is obvious that itis meant otherwise.

Finally, as used herein any reference to “one embodiment,” or “someembodiments” means that a particular element, feature, structure, orcharacteristic described in connection with the embodiment is includedin at least one embodiment of the inventive concepts disclosed herein.The appearances of the phrase “in some embodiments” in various places inthe specification are not necessarily all referring to the sameembodiment, and embodiments of the inventive concepts disclosed mayinclude one or more of the features expressly described or inherentlypresent herein, or any combination of sub-combination of two or moresuch features, along with any other features which may not necessarilybe expressly described or inherently present in the instant disclosure.

Broadly, embodiments of the inventive concepts disclosed herein aredirected to a smart steering control (SSC) system. The SSC in a pavingor texturing machine receives path elements corresponding to current andfuture positions of the machine. By comparing the current and futureelements, an expected completion time is derived for exiting the currentposition and entering the future position; the smart steering controlsystem synchronizes adjustments of the machine's steerable tracks fromthe current path to the future path. The smart steering control systemfunctions as a virtual tie rod, preventing damage, enhancing thetraction control and pulling power of the machine, and preserving theoperating life of its components.

Referring to FIG. 1, an exemplary embodiment of a tool carrier 100(e.g., a paving (or texturing) machine incorporating one or more tools)according to the inventive concepts disclosed herein may include achassis 102 incorporating an operating platform 104, from which anoperator may control the movement of the machine 100 (the tool carriermay be manually or remotely operated, or may operate autonomously). Thetool carrier 100 may include one or more tools 106 removably mounted tothe machine which may be added to or removed from the machine 100depending on job requirements. For example, the tool 106 may include,but is not limited to, a curb mold, barrier mold, trimmer, cylinder,conveyor/auger (108), sprayer, trencher, mill or like grinder, planter,grader blade, or combination of one or more of the above.

The tool carrier 100 may be universally propelled and/or steered in anyof a variety of modes (e.g., crab steering, front-only or rear-only,coordinated steering, counter-rotate steering, tool steering) via aseries of steerable crawlers, or tracks, 110. Each track 110 may bemounted to an actuator 112 for positioning the tracks 110 in a varietyof configurations, including an operational configuration shown by FIG.1 and a transport configuration (not shown) whereby the width of themachine may be minimized for efficient transport via a flatbed truck orlike vehicle. Each track 110 may further be mounted to the actuator 112via a slew drive or similar rotational actuator 114 configured toarticulate the track 110 through a full 360 degrees of rotation; in thisway, the tool carrier 100 may be steered with optimal precision byadjusting the individual rotational angle of each track. Each track 110may incorporate a pivot arm 112 a articulable by the actuator 112 (e.g.,the pivot arm 112 a and track 110 may be rotated as one relative to acommon z-axis, or the tracks 110 may be mounted to parallelogram-type ortelescoping/sliding pivot arms); the pivot arm 112 a may further beconfigured to provide grade control for the chassis 102 by raising orlowering the chassis 102 or a track 110 “up” or “down” (relative to thez-axis) via linear actuators.

Turning the tracks 110 when stopped may cause frame shift. Frame shiftcauses additional path tracking errors resulting in the tool positionbeing incorrect. By turning the tracks 110 while moving, closed-loopcontrols continuously correct such errors such that path tracking errorsdue to frame shift are reduced to negligible, acceptable levels.

The tool carrier 100 may include position sensors 116 for measuring theposition of the center of each track 110 as well as the position of thetool 106, and reporting these positions to the SSC. The position sensors116 may include smart cylinders for telescoping or parallelogram typeswing legs/pivot arms or rotation sensors for measuring a rotationalangle of the pivot arm 112 a or the track 110. The SSC may use feedbackfrom the position sensors 116, along with machine parameters specific tothe tool carrier 100 (e.g., pivot arm length, parallelogram geometry,retracted/extended positions of telescoping members) to dynamicallycalculate track and tool positions for improved steering and/or gradecontrol. The SSC may adjust its calculations based on changes to themachine parameters, e.g., if an ancillary track 118 is added or removed(see FIG. 4A), if a tool 106 is added, changed, or repositioned, or ifthe pivot arm 112 a is rotated to reposition a track 110 (which mayalter the weight distribution, center of gravity, and steeringcharacteristics of the tool carrier 100).

Referring to FIG. 2, the tool carrier 100 a may be implemented and mayoperate similarly to the tool carrier 100 of FIG. 1, except that thetool carrier 100 a may incorporate a left front (LF) track 110 a, aright front (RF) track 110 b, and a centrally mounted rear (RR) track110 c, each track 110 a-c coupled to an onboard power supply 120 fordriving the tracks and/or slew drives/rotational actuators 114. Eachtrack 110 a-c may incorporate a slew drive or rotational actuator 114and rotational angle/position sensors 116. The position sensors 116 mayreport the position of the track 110 a-c to the SSC 122, as well as therotational angle of each individual track 110 a-c, for example, relativeto a defined reference angle, e.g., a nominal angle (130, FIG. 3)parallel to a straight-line paving direction (128, FIG. 3). The SSC 122may monitor the position and configuration of the tool carrier 100 arelative to a path pre-programmed project plan as well as any resultingpath tracking error (e.g., deviation from a stringline or virtualguideline). Based on input from the SSC 122 (as well as, e.g., thecurrent geometry and/or steering parameters of the machine), thesteering control system 124 may alter the direction of travel of thetool carrier 100 a by rotating one or more of the tracks 110 a-c.

Referring to FIG. 3, the tool carrier 100 b may be implemented and mayoperate similarly to the tool carrier 100 a of FIG. 2. For straight-lineoperations, e.g., paving or trimming a straight curb or gutter 126, thetool carrier 100 b may proceed directly forward (e.g., parallel to apaving direction 128) either manually, remotely, or autonomously, eachtrack 110 a-c aligned at a nominal angle 130 (e.g., a near-zero anglealso parallel to the paving direction 128, allowing for mini- ormicro-corrections in steering by a closed-loop steering controller tominimize path tracking error). To continue operations along a differentstraight paving direction 128 a, e.g., at an angle to the initial pavingdirection 128, the tool carrier 100 b may stop at a predetermined point,rotate each track 110 a-c in unison to the target angle 130 a, andproceed along the new paving direction 128 a.

In some embodiments, a transition from a first straight paving direction128 to a second straight-line paving direction 128 a is accomplished viaaltering a front steering point to rotate the entire tool carrier 100 band maintain a tool's 106 longitudinal edge tangent to the path. In someembodiments, the transition from the first straight paving direction 128to the second straight-line paving direction 128 a is accomplished byaltering the orientation of the tracks 110 a-c without changing theorientation of the tool carrier 100 b. Such orientation may requirechanging the orientation of the tool 106.

However, certain paving or texturing operations of the tool carrier 100b may incorporate curved surfaces, e.g., curbing a curved surface 132defined by a short radius 134; for example about 0.61 m (2 feet) orsmaller, a composite curved surface defined by more than one radius, ora spiral incorporating constantly varying radii. The tool carrier 100 baccording to embodiments of the present disclosure may eliminate crosstrack error more efficiently than conventional approaches by dynamicallyanticipating and controlling target track angles 130 a and trackrotation speeds, based on changes in the position of the track 110 a-cfrom path element to path element as well as changes in the toolposition and the operator provided tool speed.

In a closed-loop system, an SSC may identify front and rear errorcomponents, and multiply such error components by a steering authorityto determine a virtual correction. The virtual correction may comprisean angle per millimeter of error. The virtual correction is added toinstantaneous target angles to provide effective angles associated withfront and rear points of the tool carrier 100 b. Given the position ofthe front and rear points, and their effective angles, a line-lineintersection function calculates an intersection, which becomes aneffective synchronization point. All track angles and propulsion speedsare then updated using the effective synchronization point to rotate thetracks 110 a-c.

Referring generally to FIGS. 4A-4E, the tool carrier 100 c may beimplemented and may operate similarly to the tool carrier 100 b of FIG.3, except that the SSC (122, FIG. 2) of the tool carrier 100 c maydefine a local coordinate system by which any component or point of thetool carrier 100 c may be defined.

For example, referring in particular to FIG. 4A, if the tool carrier 100c is to pave a small-radius curved surface (132, FIG. 3) in acounterclockwise or leftward direction, a coordinate system may bedefined relative to a tool position 136 or, alternatively, a position ofthe Rigid Machine Frame (RMF), or chassis 102, corresponding to the rearleft corner of the tool 106. Other points of the coordinate system maycorrespond to coordinate sets [x, y] relative to an origin [0, 0] at thetool position 136. Coordinate sets may include z-axis coordinates (notshown), e.g., if the path incorporates dynamic grade control betweenthree-dimensional current and future path elements or if the relativeheight of a component is otherwise essential to the path. Assuming thetracks 110 a-c remain in fixed positions relative to the tool 106 (andto the tool carrier 100 c), the tracks may be defined respectively bycoordinate points 136 a-c (corresponding to local coordinates [x₁, y₄],[x₄, y₃], and [x₂, y₀] and a midpoint of the chassis 102 defined bycoordinate point 136 d ([x₃, y₂]). The SSC may define a common rotationpoint (142, FIG. 4C) based on the local coordinate system. In order forthe SSC to more effectively anticipate the movement of the tracks 110a-c throughout the path, a future path element (look-ahead point) 138may be defined (e.g., at [x₁, y₀]) as a point or vector on the y-axiswhere y is greater than 0 or less than 0 such that when the toolposition 136 corresponds to a current path element of the curved surface(132, FIG. 3), the future path element 138 may be used by the SSC todynamically determine a curvature of the curved surface 132 at thefuture path element (and thereby the desired track angles at the futurepath element) as well as a completion time between exiting the currentpath element and entering the future path element. Based on thesedeterminations, the SSC may synchronize the rotation of the tracks 110a-c from a current position corresponding to the current path element toa future position corresponding to the future path element 138, relativeto the common rotation point, during the completion time. It should benoted that should the tool carrier 100 c be reconfigured in operatingmode, e.g., should the RF track 110 b be repositioned 110 d relative tothe chassis 102 or other tracks 110 a, 110 c, the local coordinatesystem may associate the repositioned track 110 d with a new track point136 e, and the SSC may modify its steering and rotational calculationsaccordingly.

In some embodiments, the future path element 138 and current point orcurrent path element may not be on the y-axis. Such embodiments may beuseful for plotting or otherwise incorporating offset paths. Forexample, a 3D design and 3D system places a curb in a cul-de-sac; thenusing the edge of the curb, the 3D system offsets outward to place asidewalk at a constant distance from the curb/road. The 3D system maythen modify provided design radius data to reflect the offset.Alternatively, the 3D system may modify provided alignment dataassociated with the edge of the curb with a modified future path element138/current path element x-value. The system thereby produces offsetshapes without additional CAD/Designing of new machine control files.

Referring in particular to FIG. 4B, the tool carrier 100 c may beconfigured to pave, according to path elements received from theoperator (or externally), a straight-line path (140) before entering thecurved surface 132. For example, the tool carrier 100 c may commencepaving at a point where the tool position 136 aligns with an end of theright-side straight path 140. A future path element 138 may be selecteddirectly ahead of the tool position 136 on the straight path 140.Accordingly, each track 110 a-c may remain at the nominal angle 130,aligned with the paving direction 128.

Referring in particular to FIG. 4C, the tool carrier 100 c may proceedforward such that the tool position 136 may exit the straight path 140and enter a short-radius curved path 132 defined by a small radius 134and target rotation center (common rotation point) 142. The SSC (122,FIG. 2) may monitor the progress of the tool position 136 correspondingto the current path element based on, e.g., input from the positionsensors 116. The position of the future path element 138 may indicatethat the tool 106 is proceeding into the short-radius curved path 132.As the tool 106 enters the short-radius curved path 132, the futureposition and orientation 144 a-c of each track, shown at a currentposition/orientation 110 a-c, may be determined by a radial vector 146a-c from each track to the common rotation point 142. For example, eachfuture path element corresponding to a future tool position may beassociated with a position/orientation 144 a-c of each track 110 a-cperpendicular to the radial vector 146 a-c, including, if the rear track110 d is not aligned with the tool 106, a future position/orientation144 d perpendicular to the radial vector 146 d. Similarly, based on themachine speed, which may or may not remain uniform, entry to each futurepath element 138 along the short-radius curved path 132 may beassociated with a completion time relative to the current path element.If, for example, FIG. 4B illustrates a start time to corresponding tothe current path element tool position 136 before the tool 106 entersthe short-radius curved path 132, then FIG. 4C may illustrate a futurepath element corresponding to a subsequent time t_(x) at which the toolposition 136 enters the short-radius curved path 132. The rate at whichthe LF and RF tracks 110 a-b are rotated to the desired track angles 148a-b corresponding to their position and orientation 144 a-b at thefuture path element corresponding to subsequent time t_(x) may then bedetermined based on, for example, the forward speed of the tool carrier100 c and the determined completion time defined by t_(x)-t₀ between thecurrent and future path elements.

Referring in particular to FIG. 4D, at time t_(x) the correspondingfuture path element (138, FIG. 4C) may become the current path elementcorresponding to the current tool position 136 on the small-radiuscurved path 132. Similarly, based on the updated positions of the tool106 a and the updated positions/orientations of the tracks 144 a-c theSSC may receive subsequent future path elements corresponding to futuretool positions 136 a-b, each future path element 136 a-b correspondingto a position/orientation of the tracks 110 a-c at, e.g., future timest_(y) and t_(z) (e.g., 150 a-c and 152 a-c respectively). The SSC maycalculate, based on the machine speed and completion times (e.g.,t_(y)-t_(x) and t_(z)-t_(y)) between each future path element as thefuture path element becomes a current path element and the subsequentfuture path element, the necessary synchronized rotation for each trackto maintain the small-radius curved path 132 as the tracks reach thefuture path elements at times t_(y) (positions/orientations 150 a-c) andt_(z) (positions/orientations 152 a-c) respectively.

Referring generally to FIGS. 5-7, the tool carrier 100 d may beimplemented and may function similarly to the tool carrier 100 c ofFIGS. 4A-D, except that, referring in particular to FIG. 5, the SCC ofthe tool carrier 100 d may similarly guide the tool carrier throughcurved path elements while traveling in a clockwise (e.g., “reverse”relative to the orientation of the tool carrier) direction 154, andsynchronize the rotation of tracks 110 a-c (156 a-c) topositions/orientations (158 a-c) corresponding to a future path element138 a (tool 106 c).

Referring in particular to FIG. 6, the SSC of the tool carrier 100 d maysynchronize the rotation 160 a-c of the tracks 110 a-c topositions/orientations 162 a-c corresponding to a future path element138 as the tool carrier 100 d proceeds clockwise and forward around acurved path element 166.

Referring in particular to FIG. 7, the tool carrier 100 d may proceedaround a curved path element 168 defined by multiple radii 134 a-b andmultiple common rotation points 142 a-b. The SSC of the tool carrier maysynchronize rotation of the tracks 110 a-c between a current pathelement (positions/orientations 148 a-c) and a future path element(positions/orientations 170 a-c) based on the first common rotationpoint 142 a (curved path element 168 a) or based on the second commonrotation point 142 b (curved path element 168 b) depending on thelocation of the future path element relative to the curved surface 168.

It is believed that the inventive concepts disclosed herein and many oftheir attendant advantages will be understood by the foregoingdescription of embodiments of the inventive concepts disclosed, and itwill be apparent that various changes may be made in the form,construction, and arrangement of the components thereof withoutdeparting from the broad scope of the inventive concepts disclosedherein or without sacrificing all of their material advantages; andindividual features from various embodiments may be combined to arriveat other embodiments. The form herein before described being merely anexplanatory embodiment thereof, it is the intention of the followingclaims to encompass and include such changes. Furthermore, any of thefeatures disclosed in relation to any of the individual embodiments maybe incorporated into any other embodiment.

What is claimed is:
 1. A computer apparatus comprising: at least oneprocessor in data communication with a tangible memory storingnon-transitory processor executable code for configuring the at leastone processor to: receive a path comprising at least one path elementincluding a radius portion; determine a common rotation point associatedwith the radius portion; determine a first angle associated with a firsttrack of a tool carrier, the first angle defined by a distance of thefirst track from the common rotation point; steer the first track to thefirst angle; determine a second angle associated with a second track ofa tool carrier, the second angle defined by a distance of the secondtrack from the common rotation point; steer the second track to thesecond angle; determine a third angle associated with a third track of atool carrier, the third angle defined by a distance of the third trackfrom the common rotation point; steer the third track to the thirdangle; and calculate a completion time of the at least one path elementincluding the radius portion, wherein the at least one path elementcomprises a portion of a path of a tool.
 2. The apparatus of claim 1,wherein: the path further comprises at least one path element includinga straight portion; and the processor executable code further configuresthe at least one processor to: determine a fourth angle associated withthe first track defined by the straight portion; determine a fifth angleassociated with the second track defined by the straight portion; anddetermine a sixth angle associated with the third track defined by thestraight portion.
 3. The apparatus of claim 2, wherein the processorexecutable code further configures the at least one processor to:transition the first track from the first angle to the fourth angleafter the completion time has elapsed; transition the second track fromthe second angle to the fifth angle after the completion time haselapsed; and transition the third track from the third angle to thesixth angle after the completion time has elapsed.
 4. The apparatus ofclaim 1, wherein: the at least one path element comprises a first pathelement including a first radius portion; the path further comprises asecond path element including a second radius portion distinct from thefirst radius portion; and the processor executable code furtherconfigures the at least one processor to: determine a second commonrotation point associated with the second radius portion; determine afourth angle associated with the first track defined by a distance ofthe first track from the second common rotation point; determine a fifthangle associated with the second track defined by a distance of thesecond track from the second common rotation point; and determine asixth angle associated with the third track defined by a distance of thethird track from the second common rotation point.
 5. The apparatus ofclaim 4, wherein the processor executable code further configures the atleast one processor to: transition the first track from the first angleto the fourth angle after the completion time has elapsed; transitionthe second track from the second angle to the fifth angle after thecompletion time has elapsed; and transition the third track from thethird angle to the sixth angle after the completion time has elapsed. 6.The apparatus of claim 1, wherein: the at least one path elementcomprises a variable radius curve; and the processor executable codefurther configures the at least one processor to: determine a firsttrack function for smoothly altering the angle of the first track fromthe first angle to carry a tool through the at least one path elementduring the completion time; determine a second track function forsmoothly altering the angle of the second track from the first angle tocarry a tool through the at least one path element during the completiontime; and determine a third track function for smoothly altering theangle of the third track from the first angle to carry a tool throughthe at least one path element during the completion time.
 7. A methodfor paving comprising: receiving a paving tool path comprising at leastone path element including a radius portion; determining a commonrotation point associated with the radius portion; determining a firstangle associated with a first track of a tool carrier, the first angledefined by a distance of the first track from the common rotation point;determining a second angle associated with a second track of the toolcarrier, the second angle defined by a distance of the second track fromthe common rotation point; determining a third angle associated with athird track of the tool carrier, the third angle defined by a distanceof the third track from the common rotation point; calculating acompletion time of the at least one path element, wherein the at leastone path element comprises a variable radius curve; determining a firsttrack function for smoothly altering the angle of the first track fromthe first angle to carry a tool through the at least one path elementduring the completion time; steer the first track according to the firsttrack function; determining a second track function for smoothlyaltering the angle of the second track from the first angle to carry atool through the at least one path element during the completion time;and steer the second track according to the second track function;determining a third track function for smoothly altering the angle ofthe third track from the first angle to carry a tool through the atleast one path element during the completion time; and steer the thirdtrack according to the third track function.
 8. The method of claim 7,further comprising: determining a fourth angle associated with the firsttrack defined by at least one path element in the paving tool path, theat least one path element including a straight portion; determining afifth angle associated with the second track defined by the straightportion; and determining a sixth angle associated with the third trackdefined by the straight portion.
 9. The method of claim 8, furthercomprising: transitioning the first track from the first angle to thefourth angle after the completion time has elapsed; transitioning thesecond track from the second angle to the fifth angle after thecompletion time has elapsed; and transitioning the third track from thethird angle to the sixth angle after the completion time has elapsed.10. The method of claim 9, further comprising: determining a secondcommon rotation point associated with a second radius portion, whereinthe at least one path element comprises a first path element including afirst radius portion and the path further comprises a second pathelement including the second radius portion distinct from the firstradius portion; determining a fourth angle associated with the firsttrack defined by a distance of the first track from the second commonrotation point; determining a fifth angle associated with the secondtrack defined by a distance of the second track from the second commonrotation point; and determining a sixth angle associated with the thirdtrack defined by a distance of the third track from the second commonrotation point.
 11. The method of claim 10, further comprising:transitioning the first track from the first angle to the fourth angleafter the completion time has elapsed; transitioning the second trackfrom the second angle to the fifth angle after the completion time haselapsed; and transitioning the third track from the third angle to thesixth angle after the completion time has elapsed.
 12. A tool carriercomprising: a chassis; at least three steerable tracks connected to thechassis; and at least one processor in data communication with a memorystoring processor executable code for configuring the at least oneprocessor to: receive a path comprising at least one path elementincluding a radius portion; determine a common rotation point associatedwith the radius portion; determine a first angle associated with a firsttrack in the at least three steerable tracks, the first angle defined bya distance of the first track from the common rotation point; steer thefirst track to the first angle; determine a second angle associated witha second track in the at least three steerable tracks, the second angledefined by a distance of the second track from the common rotationpoint; steer the second track to the second angle; determine a thirdangle associated with a third track in the at least three steerabletracks, the third angle defined by a distance of the third track fromthe common rotation point; steer the third track to the third angle; andcalculate a completion time of the at least one path element includingthe radius portion, wherein the at least one path element comprises aportion of a path of a tool.
 13. The tool carrier of claim 12, wherein:the path further comprises at least one path element including astraight portion; and the processor executable code further configuresthe at least one processor to: determine a fourth angle associated withthe first track defined by the straight portion; determine a fifth angleassociated with the second track defined by the straight portion; anddetermine a sixth angle associated with the third track defined by thestraight portion.
 14. The tool carrier of claim 13, wherein theprocessor executable code further configures the at least one processorto: transition the first track from the first angle to the fourth angleafter the completion time has elapsed; transition the second track fromthe second angle to the fifth angle after the completion time haselapsed; and transition the third track from the third angle to thesixth angle after the completion time has elapsed.
 15. The tool carrierof claim 12, wherein: the at least one path element comprises a firstpath element including a first radius portion; the path furthercomprises a second path element including a second radius portiondistinct from the first radius portion; and the processor executablecode further configures the at least one processor to: determine asecond common rotation point associated with the second radius portion;determine a fourth angle associated with the first track defined by adistance of the first track from the second common rotation point;determine a fifth angle associated with the second track defined by adistance of the second track from the second common rotation point; anddetermine a sixth angle associated with the third track defined by adistance of the third track from the second common rotation point. 16.The tool carrier of claim 15, wherein the processor executable codefurther configures the at least one processor to: transition the firsttrack from the first angle to the fourth angle after the completion timehas elapsed; transition the second track from the second angle to thefifth angle after the completion time has elapsed; and transition thethird track from the third angle to the sixth angle after the completiontime has elapsed.
 17. The tool carrier of claim 12, wherein theprocessor executable code further configures the at least one processorto: determine a front error associated with a front point of the toolcarrier; determine a rear error associated with a rear point of the toolcarrier; multiply the front error and rear error by a steering authorityto produce a virtual correction; add the virtual correction to each ofan instantaneous front angle and rear angle; calculate a synchronizationpoint based of a line-line intersection of the front point and rearpoint and the corrected instantaneous front angle and rear angle; andupdate an angle and propulsion speed associated with each of the atleast three steerable tracks based on the synchronization point.